The mental state of a person in Vedic language is described in terms of gunas. The present state of mind of any person is a result of mixing of three gunas of nature called tamas, rajas and satoguna. In terms of states of mind, they are called tamas, rajas and satva and the nature of a person is described as tamsik, rajsik and satwik.

Whether it is Vedas, Upanishads, Bhagwad Gita or the text of Ayurveda, all talk about these gunas. The sankhya philosophy also says that a mixture of the three makes the cosmic mind as well as the human mind. Bhagwad Gita talks in great detail about the nature, yagna as well as diet depending upon these gunas.

A satwik diet enhances satoguna in a person and makes him/her with a predominant satwik nature. The same is true for the other two gunas. According to Ayurvedic texts and in Atharvaveda. any food that comes from the roots or underground part of the tree, is tamsik in nature. Tamsik foods should not be eaten raw. They should either be slow cooked or soaked in water for hours before consumption.

Foods which are from the top part of the tree like coconut, fruits, leaves and flowers are satwik in nature and can be consumed fresh, as they are. Food which comes from the middle part of the tree is often rajsik in nature.

Fresh, soaked, sprouted, natural food are often satwik, while left over foods are tamsik in nature. Most satwik foods are naturally white.

Ramayana also has characters with different nature. Kumbhakaran represents a person with tamsik nature, Meghnad and Ravana with rajsik nature and Vibhishan with satwik nature. One can see that the diet of Kumbhakaran was left over foods, onions, radish, carrots and non vegetarian food, all are tamas producing.

Shastras also teach us about satwik food. In Vedic knowledge, God is represented by the consciousness and whatever is offered to God is the one, which is offered to consciousness and hence all offerings to God are soul healing and soul nurturing food items. Only satwik foods are offered to God as one can live on satwik food forever. Examples are dry fruits, fruits and milk. One cannot live on rajsik or tamsik food hence, they have to be taken in moderation only.

The offerings to God include honey, milk, curd, fruits and vegetables, etc. Panchamrit, offered in Puja, a mixture of milk, curd, ghee, honey and sugar, is a classic example.

Yogashastra also talks about the role of satwik diet in great detail. It says people who eat less are yogis, people who eat in moderation are bhogis and people who eat a lot are rogis. The synonymous are tamsik for rogis, rajsik for bhogis and satwik for yogis.

In terms of proper diet, one should eat dinner lighter than lunch, eat only natural food in the night and follow the principles of moderation and variety.